Structural heterogeneity in DNA gyrases from Gram-positive and Gram-negative bacteria

GyraseA (GyrA) subunit of DNA gyrase from mycobacteria has certain characte ristics distinct from that of E. coli. Polyclonal antibodies produced again st M. tuberculosis GyrA recognized GyrA from different slow and fast growin g mycobacterial species and also from several Gram-positive bacteria. Howev er, these antibodies did not cross-react with E. coli GyrA and the enzyme f rom other Gram-negative bacteria. The results from the present study togeth er with multiple alignment, pairwise comparison and biochemical properties support the idea of the occurrence of two subclasses of gyrases in the bact erial kingdom, emphasizing the importance of the enzyme as a molecular targ et for the development of novel therapeutics.